By my interpretation, the correct operator should be &&, what say you, Monks?
What prevents you from doing so? 
print "no editor found\n"
  if (!defined $ENV{EDITOR} && !defined $ENV{VISUAL});

[download]
But, I would say, 
die "no editor found\n"
  unless my $editor = $ENV{EDITOR} || $ENV{VISUAL};
print "predefined editor: $editor\n";

[download]
If you have some interpretation, just run the code to see if the result meets what you expect. Otherwise, trying to "read" the code more verbally is one way to have some grasp whenever I get a little puzzled. "If this is false: EDITOR is undefined, or, VISUAL is undefined then I have no predefined editor set". I keep repeating that until it fits mentally into my understanding. In this particular example, I usually end up with: "OK, I'll do it with unless....".

You can also talk to your teddy bear or your monitor in this process.

Update: (18-06-2007) I found bobf's True or False? A Quick Reference Guide also quite a reference with many examples and enlightening tables.

Open source softwares? Share and enjoy. Make profit from them if you can. Yet, share and enjoy!

In reply to Re^2: interpretation of "neither...nor" by naikonta
in thread Re: interpretation of "neither...nor" by cgmd

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post, it's "PerlMonks-approved HTML":


  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Titles consisting of a single word are discouraged, and in most cases are disallowed outright.
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, details, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, summary, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.